ECO from website or Steam?

I notice ECO is on Steam for about the same price as it is on the official website. However, Steam natively allows you to install a game on more than one PC so long as you log in to your Steam account. The official website for ECO says you can buy a "single" copy of the game for that price. Does this mean I would not be able to put the game on both my laptop and my desktop? I'd like to purchase the game from ECO official, but also have no qualms about Steam. Thoughts?

Best,
inderekt

EDIT: I notice a very similar question on this thread so I apologize for duplication. However, my question is a bit different as I regard licensing in question.